Assertion :- In some xerophytic plants stem becomes green , flat,leaf like and leaves are modified into spines .
Reason :-In xerophytic areas rate of transpiration is high , so plants develop various adaptions to minimize transpiration.

Options

A. (a) If both Assertion & Reason are True & Reason is a correct explanation of the Assertion.
B. (b) If both Assertion & Reason are True & the Reason is a correct explanation of the Assertion.
C. (c) If Assertion is True but the Reason is False.
D. (d) If both Assertion & Reason are false.

Answer

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that in some xerophytic plants, the stem becomes green, flat, and leaf-like, while the leaves are modified into spines.
- Example: Aloe vera is a common xerophytic plant that exhibits these characteristics.

2. **Analyzing the Reason**:
- The reason provided explains that in xerophytic areas, the rate of transpiration is high.
- To cope with this, plants develop various adaptations to minimize transpiration.

3. **Connecting Assertion and Reason**:
- The adaptation described in the assertion (stem becoming green and flat, leaves turning into spines) is a direct response to the high rate of transpiration mentioned in the reason.
- The modification of leaves into spines reduces the surface area exposed to the environment, thereby minimizing water loss.

4. **Evaluating the Truth of Both Statements**:
- Both the assertion and the reason are true.
- The reason correctly explains why the adaptations mentioned in the assertion occur.

5. **Conclusion**:
- Since both the assertion and reason are true, and the reason provides a correct explanation for the assertion, the answer is option A: both assertion and reason are true, and the reason is the correct explanation of the assertion.